I made my first arch - now i have a 27plug problem

[n1ist]

ExpressPCB has this table:
0.010" 0.3 Amps
0.015" 0.4 Amps
0.020" 0.7 Amps
0.025" 1.0 Amps
0.050" 2.0 Amps
0.100" 4.0 Amps
0.150" 6.0 Amps

and here's a good on-line calculator
http://www.desmith.net/NMdS/Electronics/TraceWidth.html
/mike

[smartalec]

Originally Posted by n1ist

ExpressPCB has this table:
0.010" 0.3 Amps
0.015" 0.4 Amps
0.020" 0.7 Amps
0.025" 1.0 Amps
0.050" 2.0 Amps
0.100" 4.0 Amps
0.150" 6.0 Amps

and here's a good on-line calculator
http://www.desmith.net/NMdS/Electronics/TraceWidth.html
/mike

thanks heaps for that..
eagle might be free, but it is frustrating to learn
Knowledge is everything.

[aussiephil]

SA.

Two things for you

I use this calculator for trace width calcs as it also allows you to specify the copper weigh
http://www.circuitcalculator.com/wor...th-calculator/

a 1A trace on 1oz copper would need a Min 12mil trace on and external layer. depending on trace length i would then decide if it should be wider.

the ULN2803 whilst everyone quotes the 500mA spec has an actual limit of 150mA/channel for 8 channels driven at 100% duty cycle, as would be the case with lights turned on at 100% intensity.
This is at 25c and would need to be derated in Oz for the normal 40c+ temp you would have in an external enclosure in the sun.

ok make that 3,
I knw you have settled on a DB connector but have a look at these
http://au.mouser.com/ProductDetail/T...liN5hDqQeB1FaE
they are available in different counts and support 22g to 28g wires, 22g is about normal xmas light wires in oz.
They allow you to use standard .100 headers on your board and provide a quick and simple connection and termination.
you can also chose to use the polarizing headers making it near foolproof in getting pos/neg around the right way when connecting leds.

Guess what i'm using on the LED 120ch controller?

Cheer
aussiephil

[smartalec]

Ok i decided to do the math with the lights,
im using the Big-W ext led lights, an cut them down into there 10led segment for green/blue, an red into 15led segments.
I was going to orginaly going to use 1 segment per arch segment,
but deceded there was'nt enouth colour so im making it 3 green/blue light segments per arch segment.
now the math, someone else allready done all this for me an it works out to be 20ma for the red led segment (15leds),
an 10ma for blue/green(10led)
at 29v.
so at 2 strings of 15red leds =40ma x 9 ch = 360ma
an 3 lots of blue/green 10 leds = 30ma x 9 ch = 270ma

so a whole arch 3 colours on = 360 + 270 + 270 = 900ma total per arch
so i hope the 4xULN2803 can handle the job of all the channels

-the plugs you meshion phil, there like the motherboard power plug arnt they? if so, them clips dont last with me,

i just want to chuck a ren64 an 2 of these boards for every 2 archs.
saves using them dc controllers .

so with all this new info in hindsite.. do i still need to fatten up tracks
thanks

Originally Posted by aussiephil

SA.

Two things for you

I use this calculator for trace width calcs as it also allows you to specify the copper weigh
http://www.circuitcalculator.com/wor...th-calculator/

a 1A trace on 1oz copper would need a Min 12mil trace on and external layer. depending on trace length i would then decide if it should be wider.

the ULN2803 whilst everyone quotes the 500mA spec has an actual limit of 150mA/channel for 8 channels driven at 100% duty cycle, as would be the case with lights turned on at 100% intensity.
This is at 25c and would need to be derated in Oz for the normal 40c+ temp you would have in an external enclosure in the sun.

ok make that 3,
I knw you have settled on a DB connector but have a look at these
http://au.mouser.com/ProductDetail/T...liN5hDqQeB1FaE
they are available in different counts and support 22g to 28g wires, 22g is about normal xmas light wires in oz.
They allow you to use standard .100 headers on your board and provide a quick and simple connection and termination.
you can also chose to use the polarizing headers making it near foolproof in getting pos/neg around the right way when connecting leds.

Guess what i'm using on the LED 120ch controller?

Cheer
aussiephil

[aussiephil]

yeah it was me that did the maths back here
http://doityourselfchristmas.com/for...?t=8909&page=4

If your going to the trouble of doing a board with the ULN's then at least work to the nominal 20mA per section and if you underdraw current who cares.

using a self imposed limit of 120mA/Ch would give roughly 60 Green/Blue or white leds and 90 led ones at 28v based on six sections each 20mA.

The plugs are more like the fan connectors though they are tougher, any .100 plug would do if you use standard .100 headers.

Always make tracks that allow for the MAX current for the package not what you plan to use.

Each ULN output track should handle 500mA, the total for each ULN should handle at least 1.5A (it will survive short transients). This means a 6A distribution from the input/fuse connector.
Having said that you could size the tracks based on a 30c-40c temp rise rather than 10c due to the likelyhood of actually using all that current
Allowing for a greater temp rise will allow the tracks to be thinner.

[budude]

btw - the ULN outputs can be doubled up to provide more power if you want. Obviously you'll need twice the footprint for the same channel count but it makes for a very clean layout.

[smartalec]

Finely gotten to knoe eagle a bit more.
now does this look better?
sch

pcb board


besides setting the drilling holes, is it ready to be made ?
cause i would hate to get dud ones made.

[n1ist]

It may just be the picture, but there are quite a few places where traces are hitting pads at rather odd angles, connecting to the side of the pad rather than to the center. The RJ45s seem to have this issue the most. Has this board passed DRC? If you look at the two RJ45s on the left, it doesn't seem like there's enoug clearance from the pads to traces leading to adjacent pads.

I'd add a silkscreen note to the power connector showing which pin is positive, and am wondering if, with all of the switching going on here, it makes sense to add a few hundred uF of bulk capacitance to the board.
/mike

[smartalec]

Originally Posted by n1ist

It may just be the picture, but there are quite a few places where traces are hitting pads at rather odd angles, connecting to the side of the pad rather than to the center. The RJ45s seem to have this issue the most. Has this board passed DRC? If you look at the two RJ45s on the left, it doesn't seem like there's enoug clearance from the pads to traces leading to adjacent pads.

I'd add a silkscreen note to the power connector showing which pin is positive, and am wondering if, with all of the switching going on here, it makes sense to add a few hundred uF of bulk capacitance to the board.
/mike

It all passed DRC, took me awhile. dont know why but the auto track route made just about every componet slightly off.. (i did start in inch's an now in mm) just a thought.

i was thinking of a 50v rated cap. but did'nt know what uf too use. (ive blew 6 up in my last design - they could'nt handle the current spikes or heat or me shorting pins)
i reckon i'll be using 24v an 36v on different boards

this is great with all this support.
thanks.

[dnesci]

In Eagle your traces can be a bit off if your grid size is set too large. I know that I have to change the grid to get traces to hit RF45 plugs correctly. Try changing the size and see if it helps.

Don